1. What is a Lens Diffraction Calculator?

Definition: This calculator estimates the diffraction angle of light passing through a circular aperture based on the frequency of light and aperture diameter.

Purpose: It helps photographers, optical engineers, and physicists understand the limitations of optical systems due to diffraction.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \theta \) — Diffraction angle (radians)
• \( c \) — Speed of light (3×10⁸ m/s)
• \( f \) — Frequency of light (Hz)
• \( D \) — Aperture diameter (meters)

Explanation: The formula calculates the angular radius of the Airy disk, which is the diffraction pattern produced by a circular aperture.

3. Importance of Diffraction Calculation

Details: Understanding diffraction helps in designing optical systems with optimal resolution and in predicting image quality limitations.

4. Using the Calculator

Tips: Enter the light frequency in Hz and aperture diameter in meters. Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the 1.22 factor in the formula?
A: This is the first zero of the Bessel function of the first kind, which appears in the mathematical solution for diffraction through a circular aperture.

Q2: How does frequency affect diffraction?
A: Higher frequencies (shorter wavelengths) result in smaller diffraction angles, meaning less diffraction blur.

Q3: What's a typical aperture diameter for cameras?
A: Camera apertures typically range from about 0.02m (f/2.8 on a 50mm lens) to 0.003m (f/22 on the same lens).

Q4: Can I calculate this using wavelength instead of frequency?
A: Yes, since c = f×λ, the formula can also be written as θ = 1.22 × λ/D.

Q5: How does diffraction affect image sharpness?
A: Diffraction spreads light, creating blur. At small apertures, this becomes the dominant factor limiting image resolution.